|
|
@@ -1299,47 +1299,6 @@ If no such file is found, then ffmpeg will search for a file named |
|
|
|
|
|
|
|
@c man end OPTIONS |
|
|
|
|
|
|
|
@chapter Tips |
|
|
|
@c man begin TIPS |
|
|
|
|
|
|
|
@itemize |
|
|
|
@item |
|
|
|
For streaming at very low bitrates, use a low frame rate |
|
|
|
and a small GOP size. This is especially true for RealVideo where |
|
|
|
the Linux player does not seem to be very fast, so it can miss |
|
|
|
frames. An example is: |
|
|
|
|
|
|
|
@example |
|
|
|
ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm |
|
|
|
@end example |
|
|
|
|
|
|
|
@item |
|
|
|
The parameter 'q' which is displayed while encoding is the current |
|
|
|
quantizer. The value 1 indicates that a very good quality could |
|
|
|
be achieved. The value 31 indicates the worst quality. If q=31 appears |
|
|
|
too often, it means that the encoder cannot compress enough to meet |
|
|
|
your bitrate. You must either increase the bitrate, decrease the |
|
|
|
frame rate or decrease the frame size. |
|
|
|
|
|
|
|
@item |
|
|
|
If your computer is not fast enough, you can speed up the |
|
|
|
compression at the expense of the compression ratio. You can use |
|
|
|
'-me zero' to speed up motion estimation, and '-g 0' to disable |
|
|
|
motion estimation completely (you have only I-frames, which means it |
|
|
|
is about as good as JPEG compression). |
|
|
|
|
|
|
|
@item |
|
|
|
To have very low audio bitrates, reduce the sampling frequency |
|
|
|
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3). |
|
|
|
|
|
|
|
@item |
|
|
|
To have a constant quality (but a variable bitrate), use the option |
|
|
|
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst |
|
|
|
quality). |
|
|
|
|
|
|
|
@end itemize |
|
|
|
@c man end TIPS |
|
|
|
|
|
|
|
@chapter Examples |
|
|
|
@c man begin EXAMPLES |
|
|
|
|
|
|
|